So this happened to me occasionally so I hope none of you cringe:

I was writing some new stacks for a new Cloud IDE that went Open Source (give them a try, they're Coder.com), and because working closely and not releasing till I please majority of people who will use it is my paradigm, I spent reasonable time to fix it. Finally everything is sunshi-

"Wait... It's already 3 in the morning? WHAT THE FUCK"

Yep I started around 21:30, finished around 03:30.

I need an alarm clock